Apparatus for spray varnishing hides and skins



Aug. 9, 1955 E. GIRAUDO 2,714,870

APPARATUS FOR SPRAY VARNISHING HIDES AND SKINS Filed May l0. 1952 2 Sheets-Sheet 1 IIIIUII.. ||||||||||I| A Aug. 9, 1955 E. GIRAUDO 2,714,870

APPARATUS FOR SPRAY VARNISHING HIDES AND SKINS Filed May 10. 1952 2 Sheets-Sheet 2 United States Patent O 2,714,870 APPARATUS FOR SPRAY VARNISHINGHIDES AND SKINS Ettore Giraudo, Turin, Italy Application May 10, `1952, Serial No. 287,107 Claims priority, application Italy May 26, 1951 2 Claims. (C1. 11s- 2) This invention relates to an apparatus for spray varnishingA hides and skins, of the type in which the hides and skins carried by an endless conveyor are coated by sprayers arranged on one or more carriages moving transversely of the direction of movement of the conveyor.

The apparatus according to this invention comprises a conveyor which maybe in the form of a wire gauze or 'a set of bars or articulated frames arranged to form an endless grid-shaped belt in a horizontal position, on which the hides and skins are placed, and one or more sprayers for the colour or dye, each of which comprises an actual sprayer and a photoelectric cell unit carried by a carriage reciprocated transversely of the conveyor in order to fully scan the surface of the latter.

Each photoelectric cell unit comprises a projector emitting a beam of light through the conveyor, said light being reiiected by a stationary mirror extending throughout the width of the conveyor on a photoelectric cell, which actuates a valve operating the sprayer for the colour or dye.

The light beam and the axis of the jet fall on the conveyor at substantially coinciding points. When the light beam is intercepted by the hide or skin, the photoelectric cell remains inoperative and holds open the valve delivering the colour. When the light beam is not intercepted and is therefore reiiected by the mirror on the cell, the latter closes the valve delivering the jet of colour or dye.

According to further characteristic features of this invention the plant comprises means for delivering a jet of air to the mirror in order to prevent any colour oozing through the wire gauze from reaching the mirror. This colour is conveyed towards a collector in which suction takes place.

The position of the projector and photoelectric cell on the carriages is adjustable for staggering the jet with respect to the light beam and advancing and delaying opening and closure of the jet, respectively, in order to satisfactorily coat the edges of the hide or skin.

Further features and advantages of the plant according to this invention will be understood from the appended specification in which reference is made to the accompanying drawings that show an embodiment thereof merely by way of example.

Figure 1 is a longitudinal section of an end portion of the apparatus;

Figure 2 is a plan view of Figure 1;

Figure 3 is a front view of a carriage guide;

Figure 4 is a section on line IV-IV of Figure 3.

The apparatus comprises a conveyor, formed in the example shown by a wire gauze 1. The wire gauze 1, which may be replaced by a set of bars or articulated frames, forms an endless belt, supported by two end drums 2 and a set of intermediate guide rollers 4, supported by a frame 5. Roller chains 6 are provided at the edges of the endless belt 1. One of the drums 2 is driven by an electric motor 3 over a chain and sprocket drive 31.

One or more varnishing units may be arranged along the conveyor 1. In the drawing, a single varnishing unit I2,714,870 Patented Aug. 9, 1955 ice is shown," itis enclosed within sheet metal casing 7, `in which openings 8 are cut for the upper run of the conveyor, and is supported by standards 32 and provided with va stationary transverse dovetail guide 9` along which a carriage 10 slidesby means of guide rollers .11. 12 denotes and endlesschain supported on end pinions 13, one of which receives motion from the motor 3 over a chain 17 and a bevel gear 14.

, The chain 12 carries a pivot 15 engaged by a slot 16 in the carriage 10 and reciprocates the carriage in a transverse direction.

Since the carriage is moved by the same motor driving the` conveyor, the resulting synchronisation of both movements ensures a uniform coating of the hides and skins with colour.

The carriage 10 is provided with a pneumatically opened sprayer 19 to which colour and compressed air are supplied through conduits 20, 21, respectively. 22 denotes an electromagnetically operated valve controlling supply of compressed air to the sprayer. The carriage is moreover provided with a projector 23 and a photoelectric cell 24.

A stationary mirror 25 is arranged in the casing 7 and spans the conveyor rellecting light emitted by the projecfor 23 on the photoelectric cell 24. A conduit 29 is further arranged in the frame and delivers a jet of air within the casing 7 in order to prevent any colour from falling onto the mirror, and convey it to a collector 30 within which suction is exerted.

The hide or skin P is simply placed on the conveyor 1 and is continuously fed to the casing 7 in which it receives the coat of colour. The carriage 10 is reciprocated transversely of the conveyor and the light beam emitted by the projector 23 scans the full surface of the conveyor on which the skin P is placed.

When the light beam 26 issuing from the projector 23 is not intercepted by the hide or skin l), it is reilected by the mirror 25, the reflected beam 26 falling on the photoelectric cell which, by means of a relay switch energised for opening, not shown, leaves the valve 22 closed, preventing the sprayer from delivering colour or dye. When the light beam is intercepted by the hide or skin P, the photoelectric cell 24 is not illuminated, the disenergized relay closes the electric circuit, opening the valve 22, and the hide or skin is coated by the jet of colour delivered by the sprayer 19 controlled by the valve 22.

Any colour that does not fall on the hide or skin and ows through the conveyor 1, is pushed back by the air stream issuing from the conduit 29, and is thereby prevented from reaching the mirror 25 and conveyed to the suction device 30. In order to satisfactorily coat also the edges of the hide or skin, the jet of colour should fall on the hide or skin slightly in advance and leave it slightly delayed with respect to the light beam. This is obtained by properly adjusting the position and orientation of the projector 23 and photo-electric cell 24.

What I claim is:

1. Apparatus for sp'ray varnishing hides and skins comprising in combination an endless conveyor shaped as a grid belt adapted to receive the hides and skins to be coated, a carriage mounted for transverse reciprocation above the upper run of said conveyor, at least one spray gun for the spray iluid mounted on said carriage, supply means for supplying spray iluid to said spray gun, photoelectric control means, comprising a light beam projector and a photo-electric cell, spaced from each other, mounted on said carriage and both focussed on a common sp'ot lying on a stationary mirror beneath the upper run of said conveyor spanning the whole width of the grid belt, and parallel with the direction of movement of said carriage, the spray nozzle of said spray gun being substantially directed towards the point on the upper run of said conveyor which is intermediate between the points in which the light beam from the projector and the light beam directed towards the photo-electric cell reach the surface of said upper run, control means operatively connected between said photo-electric means and said supply means, whereby the supply of spray iluid is stopped when the light beam from the projector reected by the mirror strikes the photo-electric cell and started when said light beam no longer reaches said cell respectively, and means for preventing the spray uid jet passing the upper run of the grid belt from reaching the mirror.

2. Apparatus for spray varnishing hides and skins com prising in combination an endless conveyor in the form of a grid belt adapted to receive the hides and skins to be coated, a carriage mounted for reciprocation transversely above the upper run of said conveyor, at least one spray gun for the spray uid mounted on said carriage, supply means for supplying spray iluid to said spray gun, photoelectric control means, comprising a light beam projector and a photo-electric cell spaced from each other,

mounted on said carriage and both focussed on a common spot lying on a stationary mirror beneath the upper run of said conveyor spanning the whole width of the grid belt, and parallel with the direction of movement of said carriage, the spray nozzle of said spray gun being substantially directed towards the point on the upper run of said conveyor which is intermediate between the points in which the light beam from the projector and the light beam directed towards the photo-electric cell, respectively, reach the surface of said upper run, control means operatively connected between said photo-electric means and said supply means, whereby the supply of spray fluid is stopped when the light beam from the projector reflected by the mirror strikes the photo-electric cell and started when said light beam no longer reaches said cell respectively, means for adjusting the position of the light beam projector and the photo-electric cell, whereby the position of the spray nozzle may be staggered with respect to the light beam so as to advance or delay starting and stopping, respectively, the supply of the spray uid from the .spray gun, and means for preventing the spray uid jet passing the upper run of the grid belt from reaching the mirror.

References Cited in the file of this patent UNITED STATES PATENTS 465,461 Claus Dec. 22, 1891 1,264,358 Willwerscheid Apr. 30, 1918 2,072,948 Gels Mar. 9, 1937 2,281,169 Pattison Apr. 28, 1942 2,293,881 Bailey Aug. 25, 1942 2,400,315 Paasche May 14, 1946 2,459,324 Kellner Jan. 18, 1949 2,488,519 Andrews et al Nov. 22, 1949 2,505,179 Gaythwaite Apr. 25, 1950 2,561,198 Griffin et al July 17, 1951 

